Have you seen this source?

http://blog.lightingcatalog.com/bid/21366/Recessed-Lighting-Design-Guide

Planning A Room

Recessed LightingA spacing of 6' to 8' will provide even light distribution throughout a room. A spacing of 12' to 14' will provide a softer ambient light.

The first light should be about 3' away from the wall. Placing the light closer to the wall will create more reflection into the room and make the space feel brighter. Placing the lights farther away will make the corners seem dark, visually lowering the ceiling.

I have not seen that source. Thank you so much for your reply.

That article is assuming a 75 watt (1500 lumens) halogen bulb in a 6" recessed can. A 4" can will be restricted to a 50 watt (800 lumens) bulb. Your ceiling is not high enough to spread out the light sufficiently at counter height for that spacing described in the kitchen section of the article. Or at coffee table height for the general room. For a general room, you would need closer to 5' apart and 24-30" from the wall.

Consider two circuits, dim-able, one that highlights the corners of the room, the other that fills the gaps. You'll have accent lighting where you want it and total control over light levels. Clear alzak, black baffle recommended for best effect of light as opposed to glaring fixtures. Have fun!

PAR, MR, and directional LED lights have their own reflectors which make a white trim that blends with the ceiling a good choice. That mostly leaves CFL bulbs for use with alzak trims. In the 4" can, a dedicated CFL housing is best with a built-in blast because the alzak trims hold in the heat on a standard CFL w/ ballast and they burn out much quicker.